1. Field of the Invention
This invention pertains generally to the field of cockpit indicators or display units that provide flight information of a runway environment to the pilot or flight crew of an aircraft, and more particularly to synthetic vision systems (SVS), enhanced vision systems (EVS), or combined SVS-EVS.
2. Description of the Related Art
The display of information on a Head-Up Display (“HUD”) unit is a tradeoff between providing valuable information to the pilot and obscuring the pilot's view of the scene outside the aircraft. One area of major concern is the pilot's view when the pilot is flying an approach procedure to the runway for landing. The runway surface and runway lights in the real world scene need to be clear and not obscured.
As discussed by Chiew et al in U.S. patent application Ser. No. 12/217,458 entitled “System, Apparatus, and Method for Generating Runway Visual Aids on an Aircraft Display Unit,” a traditional display of a runway on a Head-Down Display (“HDD”) unit as generated in an SVS is shown as a solid surface with runway-related marking markings. Data representative of airport surfaces and airport visual aids may be obtained from a runway database. Airport surfaces include, but are not limited to, locations and information delineating or defining locations of runways, taxiways, and apron areas, fixed based operators (“FBOs”), terminals, and other airport facilities. Airport visual aids include, but are not limited to, airport pavement markings, runway markings, taxiway markings, holding position markings, airport signs, mandatory instruction signs, location signs, direction signs, destination signs, information signs, and runway distance remaining signs.
Runway related-markings increase the pilot's situational awareness of the runway environment, especially when the airport is not nearby. Although these markings may provide a benefit, they may become a detriment as the aircraft approaches the runway and the pilot lands on the runway. Such markings may produce a source of clutter and/or pilot frustration when they are presented with a constant intensity and/or brightness while the pilot has the actual runway in sight in the scene outside the aircraft.